PROJECT SUMMARY/ABSTRACT Stroke often results in numerous physical impairments that limit functional mobility, making it the leading cause of long-term disability in the United States. A primary goal for rehabilitation professionals and stroke survivors is to improve walking abilities. Despite significant efforts to improve walking, many stroke survivors are unable to walk independently after their stroke. This is in part due to variability in how stroke survivors respond to rehabilitation interventions. Because motor learning is the foundation for effective rehabilitation interventions, variability in locomotor learning after stroke is one source of this variability. To date, there is almost no information on factors that account for this variability, making if challenging to customize post stroke rehabilitation interventions. Previous research has examined demographic information and sensorimotor impairments as potential factors to explain variability in locomotor learning after stroke; however, these factors have not been found to explain a significant portion of variability. In healthy adults, cognition has been found to explain variability in learning upper extremity tasks, but this has not been examined in walking or after stroke, where cognitive deficits are common. Thus, the overall goal of this proposal is to determine the relationship between cognition and locomotor learning after stroke. In Aim 1 we will examine the relationship between learning a new walking pattern and fluid cognition in stroke survivors. In Aim 2, we will examine the relationship between remembering the new walking pattern (i.e. retention) and fluid cognition in stroke survivors. The results of this project will address critical gaps in our understanding of locomotor learning after stroke and allow us to better customize rehabilitation interventions to optimize post stroke outcomes. Additionally, this proposed work serves as a first step towards the long-term goal of this fellowship applicant, which is to become a successful clinician scientist focused on developing personalized rehabilitation interventions that optimize functional recovery after stroke. By completing this fellowship proposal under the guidance of experienced mentors in a strong research environment, the applicant will receive the training needed to successfully complete the proposed work, to develop into a productive scientist, and to achieve her long term career goals.